Can I use my ubuntu server without a gfx card to render?
If you have packaged your external assets with your .blend file, such that when referencing these assets you're looking for UV map images in, say, "//Assets/UVMaps/", you should be able to simply use the command line to render.  The trick is to use the -b (batch) switch:

blender -b [file].blend

which will give you headless (no GUI) operation.  Next up are a few command line options:


-S : select the scene to be rendered
-a : render the full animation (only applicable if you're doing an animation)
-f : render a specific frame (should not be used with -a)
-F : the output format to utilize (this may already be set up in your .blend)
-o : save the rendered output to a specific file (not needed if you've already set this up in your .blend)


For a single frame of an animation, your command line may look like this:

blender -b [file].blend -S [scene] -f [frame number] -F PNG -o frame_######.png

For the full animation, your command line may look like this, assuming you've already set the format and output parameters in the .blend file:

blender -b [file].blend -S [scene] -a

Note that if your .blend has only one scene, or if you have saved your .blend such that the active scene is the one you wish to have rendered, -S is optional.

If you're still getting errors, to better diagnose what's going on I know that I for one will need to see what the actual error log is.